Conventional tape drives, such as those used in data archival tape systems, are designed for use with a standard size tape cartridge, such as that depicted in FIG. 1. Exemplary dimensions of the tape cartridge 10 are 8 cm wide (W.sub.I) by 6 cm deep (arrows D) and 1.4 cm high. The tape cartridge 10 has two tape reels 12 which are driven by a drive capstan 14. Guide posts 15 guide the tape 17 from the reels past a cartridge door 16. The cartridge door 16 is provided on the front end of the tape cartridge 10 and is pivoted around a pivot 18 to swing open in the direction of arrow 19. When the cartridge door 16 is open, the tape 17 is exposed to a recording head (not illustrated) for recording on the tape 17.
FIGS. 3-5 depict a portion of a standard tape drive 21 and the insertion of the standard tape cartridge 10 into that drive. The tape drive 21 has a mouth 23, and a stationary door opener 25 within the mouth 23. The sequence of FIGS. 3-5 demonstrate the pivoting of the cartridge door 16 upon insertion of the tape cartridge 10 by the door opener 25 when the outer edge 20 of the cartridge door 16 is pushed against the door opener 25. In FIG. 3, the tape cartridge 10 is about to be inserted into the drive, positioned in alignment with the drive mouth 23. As the cartridge 10 enters the drive 21, shown in FIG. 4, the cartridge door 16 begins to pivot open as it is brought into contact with opener 25. Once the cartridge door 16 is open and the tape cartridge 10 fully inserted (FIG. 5), the tape 17 in the tape cartridge 10 is exposed to recording head 27.
With increases in system memory capacity, there is a need for increased archival capacity. This can be provided by higher capacity tape cartridges, containing a longer tape than contained in the standard tape cartridges 10. Due to the greater length of tape, an increased capacity tape cartridge will necessarily be larger in size than a standard tape cartridge 10. However, tape drives that can accommodate a larger capacity tape cartridge should also be able to accommodate a standard capacity tape cartridge to provide users with the option of which tape cartridge to use in a particular circumstance.
One type of higher capacity tape cartridge has a front end (the load side) that is necked down to 8 cm wide to fit into a standard size drive mouth. A top view of an embodiment of such a tape cartridge with increased archival capacity is depicted in FIG. 2a. This high capacity tape cartridge 30 contains the same internal elements as that of the standard tape cartridge 10 of FIG. 1. Hence, the high capacity tape cartridge 30 has tape reels 32, drive capstan 34, and guide posts 35. The tape cartridge 30 also has a cartridge door 36 pivotally mounted at pivot 38.
FIGS. 2b and 2c depict the outer housing of the high capacity tape cartridge 30. The outer housing has recessed guides 31 formed by longitudinally extending recesses in the top surface of the outer housing. These guides 31 interact with corresponding guiding elements in the door of the tape drive to provide a guiding of the tape cartridge 30 as it is inserted into a tape drive.
The front end 37 (the load end) of the tape cartridge 30 has the same width (e.g., 8 cm) as the front end of the standard tape cartridge 10. However, to provide the increased capacity for holding the longer tape, the housing 40 of the high capacity tape cartridge 30 is both deeper and wider toward the rear end 39 of the cartridge 30. As exemplary dimensions, when the high capacity tape cartridge 30 has an inner width W.sub.I of 8 cm (the same as the width W.sub.I of the standard tape cartridge 10), the outer width W.sub.O is 9.5 cm, and the depth D is 7.2 cm. The height of the high capacity tape cartridge 30 is the same as that of the standard capacity tape cartridge 10.
The widened rear end 39 of the high capacity tape cartridge 30 prevents the tape cartridge 30 from being inserted in a standard tape drive to the extent necessary to fully open the cartridge door 36. In order to insert such a higher capacity tape cartridge 30 into a standard tape drive, a drive mouth 41 must be made wider and a cartridge door opener 43 within the drive mouth 41 must be positioned inwardly toward the recording head 45, such as depicted in FIG. 6a. However, simply making the drive mouth 41 of a tape drive wider and moving the door opener 43 inward to accommodate a larger tape cartridge 30, causes the cartridge door 36 to open too late and hit the recording head 45. FIG. 6b depicts a partially inserted tape cartridge 30, and this late opening of the cartridge door 36.
There is therefore a need for a tape drive that can accommodate both the standard capacity tape cartridges and the higher capacity tape cartridges, and still ensure that the cartridge door of the tape cartridges will clear the recording head as the tape cartridges are inserted into the tape drive.